Primary hyperaldosteronism secondary to unilateral adrenal hyperplasia: an unusual cause of surgically correctable hypertension. A review of 30 cases

Introduction: Unilateral adrenal hyperplasia (UAH) is a rare, surgically correctable cause of primary hyperaldosteronism (PH). We report 2 cases and review the literature for cases of PH secondary to UAH successfully treated via surgery. Methods: Two cases of UAH treated at our institution were retrospectively reviewed. In addition, we reviewed 28 cases of UAH previously reported in the English literature. Results: Median patient age was 49 (range: 10-62) years, with a male to female ratio of 1.71. All patients were hypertensive, with a median preoperative systolic and diastolic blood pressure of 170 (range: 135-250) mmHg and 110 (range: 75-140) mmHg, respectively. Most patients were hypokalemic, with a median serum potassium level of 2.8 (range: 1.4-3.9) mmol/l. Ten out of 13 patients (77%) who underwent postural studies had a decrease or no change in the plasma aldosterone level, suggesting a unilateral source of hyperaldosteronism, and 9/17 patients (53%) who underwent a Computed tomography (CT) scan were correctly localized. Twelve patients underwent adrenal scintigraphy with or without dexamethasone suppression, of whom 6 (50%) were correctly localized. In 1 patient, adrenal scintigraphy demonstrated localization to the opposite gland. Adrenal venous sampling (AVS) was performed in 22 patients and successfully localized the lesion in all the patients. At a median follow-up of 12 (range: 3-96) months post-surgery, 47% of patients (14/30) were completely cured of their hypertension and 50% (15/30) had improved control. All 30 patients were cured of hypokalemia. Conclusion: Although the existence of UAH remains controversial, it is increasingly accepted as a unique pathologic entity and has an excellent outcome after unilateral adrenalectomy.